C. F. Keil and Franz Delitzsch on Ecclesiastes 12:1

Ecc 12:1

With Ecc 12:1 (where, inappropriately, a new chapter begins, instead of beginning with Ecc 11:9) the call takes a new course, resting its argument on the transitoriness of youth: “And remember thy Creator in the days of thy youth, ere the days of evil come, and the years draw nigh, of which thou shalt say: I have no pleasure in them.” The plur. majest. בּוראיך = עשׂים as a designation of the Creator, Job 35:10; Isa 54:5; Psa 149:2; in so recent a book it cannot surprise us, since it is also not altogether foreign to the post-bibl. language. The expression is warranted, and the Midrash ingeniously interprets the combination of its letters.It finds these things expressed in it, partly directly and partly indirectly: remember בארך, thy fountain (origin); בורך, thy grave; and בוראיך, thy Creator. Thus, Jer. Sota ii. 3, and Midrash under Ecc 12:1.

Regarding the words 'ad asher lo, commonly used in the Mishna (e.g., Horajoth iii. 3; Nedarim x. 4), or 'ad shello (Targ. 'ad delo), antequam. The days of evil (viz., at least, first, of bodily evil, cf. κακία, Mat 6:34) are those of feeble, helpless old age, perceptibly marking the failure of bodily and mental strength; parallel to these are the years of which (asher, as at Ecc 1:10) one has to say: I have no pleasure in them (bahěm for bahěn, as at Ecc 2:6, mehěm for mehěn). These evil days, adverse years, are now described symptomatically, and that in an allegorical manner, for the “ere” of Ecc 12:1 is brought to a grand unfolding.